Recently, due to an increase in social stress, along with environmental pollution, westernized dietary habits, such as instant food, frequent perming and dying of hair etc., the population of people with hair loss is gradually increasing. The cycle of hair growth can be divided into anagen stage during which the hair grows, catagen stage during which the hair growth ends and the hair bulb shrinks, telogen stage during which the dermal papilla stops its activity and the hair is retained in the scalp, and exogen stage during which the dermal papilla starts its activity or new hair grows, resulting in shedding of old hair.
The Anagen Stage (2 to 7 years) is the period during which the hair grows, and is divided into two stages of producing hair which grows outwards from the bulb into hair follicles and generating hard keratins in the hair follicles. The hair continues to grow itself until the catagen stage.
The Catagen Stage (2 to 3 weeks) is the period during which the growth ceases and the metabolism slows down while maintaining the shape of the hair, and keratin is not produced at this stage. The catagen stage accounts for 1% of total hair growth. At this stage, the hair bulb shrinks and divides into dermal papilla, and is surrounded by hair follicles and travels upwards, and the cell division is ceased.
The Telogen Stage (3 months) is the period during which the dermal papilla shrinks and the hair follicle gradually shrinks, and the hair root crawls upwards and falls out. It is the period of hair loss until the next stage of growth and lasts for 3 to 4 months.
Normal people have hair mostly in the anagen stage, but people with alopecia have hair mostly in the telogen stage, and thus a phenomenon of hair loss is visible with naked eye. As the hair loss progresses, the period of the anagen stage is shortened, resulting in the miniaturization of the hair. Accordingly, in order to treat the hair loss, it is important to allow the hair follicle in the telogen stage to enter rapidly to the anagen stage and to prolong the anagen stage.
Male-pattern alopecia is a phenomenon which occurs due to the male hormone testosterone, and when the testosterone is converted to dihydrotestosterone (DHT), which is a more stronger hormone, by 5α-reductase, this hormone acts on the hair follicle to induce the hair follicle from the anagen stage to the telogen stage, thereby causing hair loss. Accordingly, a method of inhibiting the production of DHT by 5α-reductase is mainly used to treat male-pattern alopecia.
Female-pattern alopecia is caused mainly by a decrease in the amount of estrogen after menopause. Minoxidil or estrogen are mainly used as therapeutic agents for female-pattern alopecia.
Alopecia areata is an autoimmune disease, but is caused by mental stress or genetic predisposition. The cause of the alopecia areata is fundamentally different, from those of androgenetic alopecia, and the treatment method is also different. Thus, methods of treating adrenocortical hormone are used, or methods of applying minoxidil to the affected area or of artificially inducing irritation to the affected area are used.
For such various and complex causes of hair loss, the components for promoting blood circulation, inhibiting male hormone function, strengthening the function of hair follicle, etc., are sold as commercialized products. However, none of them has shown a definite effect, and the problem of side effects is often raised. For example, it has been reported as adverse effects that minoxidil had sticky feeling of use and cause irritation to the skin. In the case of finasteride, it is currently used as a preparation for oral administration, but adverse effects, such as sexual dysfunction, have been reported according to its consumption, and it was inconvenient to use because it is expected to be effective only by oral administration.